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From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Graph and analysis of spring periodicity, plotting frequency against deflection to evaluate suspension characteristics.

Identifier  ExFiles\Box 178\1\  img179
Date  28th August 1926 guessed
  
- 7 -

Graph 2. shews approximately the meaning of this formula expressed graphically.

GRAPH 2.
SPRING PERIODICITY.

Y-AXIS: FREQUENCY PER MIN.
X-AXIS: SPRING DEFLN INS.

GRAPH DATA LABELS:
PERIOD
R.R. FRONT SPRING
R.R. DRAWING DEFLN. REAR SPRING.
R.R. REAR NORMAL SPRINGING.
REGION OF SEA SICKNESS IF UNDAMPED.

It will be seen that the R-R rear suspension already approaches the very low periodicity associated with sickness.
With 8" rear deflection and 3" front deflection the frequencies are not very far from a 2 - 1 ratio. This is undesirable from the point of view of pitching. It is one of the difficulties brought up by the fact that front wheel brakes necessitate strong front springs to provide adequate axle control.

contd.
  
  


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